我很难从12月(上个月的第3个月)开始抓到行。我试图计算在一定时间内销售的产品数量。这是我当前的查询:
SELECT
a.id,
a.default_code,
(
SELECT SUM(product_uom_qty)
AS
"Total Sold"
FROM
sale_order_line c
WHERE
c.product_id = a.id
),
(
SELECT SUM(product_uom_qty)
AS
"Month 3"
FROM sale_order_line c
WHERE
c.product_id = a.id
AND
MONTH(c.create_date) = MONTH(CURRENT_DATE - INTERVAL '3 Months')
AND
YEAR(c.create_date) = YEAR(CURRENT_DATE - INTERVAL '3 Months')
)
FROM
product_product a
DB就是这样的:
sale_order_line
product_id product_uom_qty create_date
33 230 2014-07-01 16:47:45.294313
product_product
id default_code
33 WHDXEB33
这是我收到的错误:
ERROR: function month(timestamp without time zone) does not exist
LINE 21: MONTH(c.create_date) = MONTH(CURRENT_DATE - INTERVAL
有什么能帮我指出正确的方向吗?
最佳答案
使用date_trunc()计算时间戳界限:
SELECT id, default_code
, (SELECT SUM(product_uom_qty)
FROM sale_order_line c
WHERE c.product_id = a.id
) AS "Total Sold"
, (SELECT SUM(product_uom_qty)
FROM sale_order_line c
WHERE c.product_id = a.id
AND c.create_date >= date_trunc('month', now()) - interval '2 month'
AND c.create_date < date_trunc('month', now()) - interval '1 month'
) AS "Month 3"
FROM product_product a;
要获得十二月(现在是二月),请使用以下表达式:
AND c.create_date >= date_trunc('month', now()) - interval '2 month'
AND c.create_date < date_trunc('month', now()) - interval '1 month'
date_trunc('month', now())
生成“2015-02-01 00:00”,减去2个月后,得到“2014-12-01 00:00”。所以,“3个月”可能是骗人的。此外,请确保使用sargable表达式(如演示)以获得更快的性能并允许使用索引。
选择
根据实际的数据库设计和数据分布,这可能更快:
SELECT a.id, a.default_code, c."Total Sold", c."Month 3"
FROM product_product a
LEFT JOIN (
SELECT product_id AS id
, SUM(product_uom_qty) AS "Total Sold"
, SUM(CASE WHEN c.create_date >= date_trunc('month', now()) - interval '2 month'
AND c.create_date < date_trunc('month', now()) - interval '1 month'
THEN product_uom_qty ELSE 0 END) AS "Month 3"
FROM sale_order_line
GROUP BY 1
) c USING (id);
因为您正在选择所有行,所以这可能比相关子查询更快。在这方面,在你加入之前先汇总一下,这样比较便宜。
当选择一个或几个产品,这实际上可能会慢,虽然!比较:
Aggregate a single column in query with many columns
Optimize GROUP BY query to retrieve latest record per user
或者在9.4+后加上
FILTER
子句:...
, SUM(product_uom_qty)
FILTER (WHERE c.create_date >= date_trunc('month', now()) - interval '2 month'
AND c.create_date < date_trunc('month', now()) - interval '1 month'
) AS "Month 3"
...
细节:
Select multiple row values into single row with multi-table clauses
关于sql - 前三个月的值总和,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/28636191/